New blood test from Epic Sciences matches patients with PARP inhibitors

San Diego-based liquid biopsy company Epic Sciences has announced a new blood test that may quickly identify cancer patients who respond to a promising class of drugs called poly ADP ribose polymerase (PARP) inhibitors. The test works by identifying circulating tumor cells (CTCs) affected by homologous recombination deficiency (HRD), a damaged DNA repair mechanism.

While many liquid biopsy technologies sequence cell-free DNA, Epic’s test uses advanced imaging to differentiate cells with HRD. The system strips out red blood cells, stains the millions of remaining nucleated cells to identify their nuclei, cytoplasm and key proteins and images them with single cell resolution. The test then sifts through the cells to identify the visual differences associated with HRD, providing results within a few days.

“When you have a genome that’s not repairing itself functionally, it generates different looking tumor cells,” said Ryan Dittamore, vice president of Translational Research and Clinical Affairs at Epic. “We’re using a digital pathology approach to identify how these cells differ in size, shape and protein expression between those that have HRD and those that don’t. We can do this really quickly since we don’t have to analyze gigabytes of genomic data.”

The PARP enzyme is a promising therapeutic target because it also repairs DNA damage, helping cancer cells survive. Inhibiting PARP in HRD cancer cells generates more damage than the cells can withstand, ultimately killing them. The trick is identifying which patients have HRD cells and will benefit from these drugs.

According to Epic, the system has already been incorporated into several clinical trials to identify the patients most likely to respond to PARP inhibitors. The test’s accuracy was recently validated against sequencing in a study conducted with Memorial Sloan Kettering Cancer Center and presented at the ASCO conference.

As more PARP inhibitors come on the market, Epic anticipates the test will shift from trials to clinical care, helping doctors select which patients will benefit most.

“We’re focused on resolving clinical decisions that physicians face,” said Dittamore. “There’s a fork in the road and our tests help tell them which way to go.”

Epic Sciences was founded in 2008 from research from San Diego’s Scripps Research Institute. In 2014, it raised $30 million to use its novel software tools to identify cancer cells as cancer’s varying nature makes it challenging to develop a catch-all test to pinpoint whether individual mutated cells are cancerous or not.

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